Silencer



Nov. 19, 1929.

H. P, MAXIM SILENCER Filed Sept. 8, 1925 m 7% m M w & x h WXQN\UJLW m IWHIIHH, W QM.

Patented Nov. 19, 1929 UNITED HIRAM PERCY MAXIM, 0F HARTFORD, CONNECTICUT, ASSIGNOR TO THE MAXIM SILENCEB- COMPANY, OF HARTFORD, CONNECTICUT, A. CORPORATION OF CONNECT- ICUT SILENCER Application filed September This invention relates to silencers for quieting the noise of explosive engines and the like and in its present embodiment is more particularly designed for' use in connection with automobile engines.

The features desired in a silencer for such purposes, in addition to the greatest possible I efficiency in the elimination of explosive noises coupled with a minimum of back pressure from exhaust gases, are lightness in weight, compactness and cheap cost. The aim of the present invention is to provide a silencer of an improved type fulfilling such requirements and one so designed that it may be constructed largely if not entirely of sheet metal built up and assembled in a manner suited to the use of standard raw materials, automatic tools and quantity production, whereby a very low manufacturing cost there for may be attained.

Further advantages and objects of the invention will become apparent from the following description taken in connection with the accompanying drawings which show the preferred embodiment of the invention and in which Fig. 1 is a longitudinal sectional view of the silencer with end portions thereof in elevation;

Fig. 2 is a cross sectional view along line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary perspective view of the end of one of the silencer tubes.

Referring more particularly to the drawings, the silencer is made up of a plurality of tubes 1, 2, 3, 4, 5 and 6, each of a different diameter and concentrically arranged to provide a series of annular passages therebetween. Each of these tubes may be conveniently made of sheet metal bent into a cylindrical form with an overlapped joint. For

8, 1925. Serial No. 55,041.

portions 7 of each tube are located in out of line relation or out of register position with respect to the ofiset portions in the next adjacent tube. Thus the offset portions 7 of each tube abut against the wall of the next adjacent inner tube for giving the spaced relation desired and at these points of abutment or contact I preferably secure the several tubes together in permanent fixed relationship by welding or riveting, as indicated at 8. The location of the offset portions 7 adjacent the ends of the tubes and in out of line relation facilitates the welding or riveting of the several tubes together by power machinery.

The concentrically arranged tubes are interposed between headers 9 and 10, the first named header being annular in form with a central orifice coincident with the inlet 11 to said innermost tube and having at its periphery an outwa ily turned flange 12 for, being secured to the outermost tube. The header 10 is of disk form with a peripheral outwardly turned flange 13 for being secured to the next outermost tube 5. The header 9 acts to close one end of the several annular passages between the tubes and the header 10 serves to close the other end of said annular passages except the outermost passage between tubes 5 and 6. One end of tube 6 preferably has an over-turned portion 14 for looking around the flange 12 of header 9 and be ing secured thereto. The other end of said tube 6 is secured to a cone shaped extension 15 which converges rearwardly of the silencer to an outlet orifice 16 which is of approximately the same area as the inlet opening 11 of said silencer. One end of tube 5 has an over-turned portion 22 for locking around the flange 13 of said header 10 and is thus secured thereto.

Each of the tubes of said silencer except the outermost tube 6 is provided with a series of ports such as 17 preferably located in longitudinal line and at one side only of said tubes for furnishing communication between the several annular passages. The line of ports 17 in each tube is displaced to one side of a radial plane intersecting the line of ports in the next adjacent tube, as shown more particularly in Fig. 2, and for a purpose hereinafter described.

For convenient application of the silencer to theend of an exhaust pipe, shown in dotted lines at 21, a tubular clamp 18 may be provided abutting the header 9 and embracing the inner end of said tube 1. Said clamp has a split portion 19 and collar 20 for receiving the usual elampingscrew.

The action of the silencer upon the dis-' charge,;gases and sound waves may be described as 'follows. The discharge gases, which have but small effect in producing the main sound which is to be quieted, pass freely into the innermost tube 1 and are conducted without great restriction by the ports '17 successively through the several annular passages to the peripheral outlet opening adjacent 22 between header 10 and tube 6 and thence through the discharge cone 15 and orifice 16. By this circuitous route through the silencer, the gas discharge pulses are sufficiently smoothed out so as to produce practically no blow on the air at the discharge orifice 16 for creating sound. The main noise to be quietedfwhich originates at the valve opening of the engine, proceeds as a sound Wave of considerable magnitude into the interior of tube'l' and is therein partially trapped. A portion of this sound wave, however, cscapes through the first series of ports 17 into the innermost annular passage. Upon entering this passage, the escaping portion of said wave will separate, one half of the same traveling to the right around said passage and one half to the left, toward the next series of escaping ports 17. But since the distances i said different directions between said first and second series of ports are unequal, the divided portions of the sound Wave will arrive at the second series of ports at different times. Such further subdivided portions of said sound wave as enter the second series of ports 17 will do so successively and this ac tion will be repeated throughout the several passages and ports until said subdivided portions of the original sound wave will emerge from the discharge exit 16 as a series of miniature waves, each of such greatly diminished energy as to be hardly perceptible to the can It will be observed that the design of the silencer is such that greater or less effectiveness in noise elimination may be accomplished by varying the number of concentric tubes and passages with but slight modification of the parts although it should be noted that a slightly greater check is offered to the free discharge of gas with any appreciable increase in said number of tubes and while this resistance to gas flow may be decreased by widening the passages, the proper design for a compact and efiicient automobile silencer will dictate proportions approximately as shown.

While the foregoing is a complete and, de-

tailed description of a preferred form of my invention, it willbe understood that it may be embodied in still other forms and variations in detail within the scope of the appended claims by which my invention is more particularly defined.

Claims:

1. A silencer comprising a plurality of cylindrical tubes of different dlameter concentrically arranged to provide a series of annular passages therebetween, said-tubes being held in radially spaced relation by a series of circumferentially spaced indented integral portions of said several tubes adjacent the opposite ends thereof, the indented portions of adjacent tubes being in outvof line relation, and the several inner tubes having ports for communication between said series ofpassages.

2. A silencer comprising a plurality of cylindrical tubes of different diameter concentrically arranged to provide a series of annular passages therebetween, said tubes being held in radially spaced relation by a series of circumferentially spaced indented integral portions of said several tubes adjacent the opposite ends thereof, the indented portions of adjacent tubes being in out of line relation,

n ing held in radially spaced relation by a series of circumferentially spaced indented integral portions of said several tubes adjacent the opposite ends thereof, the indented portions of adjacent tubes being in out of line relation, and the several inner tubes having ports for communication between said series of passages, the ports in each of said inner tubes being displaced to one side of the radial plane intersecting ports of the next adjacent tube or tubes.

4;. A silencer comprising a plurality of tubes of different diameter concentrically arranged to provide a series of annular passages therebetween, said tubes being held in radially spaced relation by a series of circumferentially spaced indented integral portions of said several tubes adjacent the opposite ends thereof, the indented portions of adjacent tubes being in out of line relation, and the several inner tubes having ports for communication between said series of passages, an annular header closing one end of said several annular passages with its central opening coinciding with the inlet to the innermost tube, and a disk header closing the other end, of said several annular passages except the outermest to provide a peripheral outlet from said series of passages.

5. A silencer comprising a plurality of flange fastened to the end of the next outertubes of different diameter concentrically armost tube.

ranged to provide a series of annular passages therebetween, said tubes being held in ra- 5 dially spaced relation by a series of circumferentially spaced indented integral portions of said several tubes adjacent the opposite ends thereof, the indented portions of adjacent tubes being in out of line relation, said several tubes being fastened to one another at said indented portions, and the several inner tubes having ports for communication between said series of assages, an annular header closing one on of said several an- 5 nular passages with its central opening coinciding with the inlet to the innermost tube, and a disk header closing the other end of said several annular passages except the outermost to provide a peripheral outlet from said series of passages, the outermost tube being fastened at one end to the periphery of said annular header and the next to the outermost tube being fastened at one end to the periphery of said disk header.

6. A silencer comprising a plurality of tubes of different diameter concentrically ar ranged to provide a series of annular passages therebetween, said tubes being held in radially spaced relation by a series of circumferentially spaced indented integral portions of said several tubes adjacent t e op 0- site ends thereof, each of said inner tu es having a longitudinal line of ports only at one side thereof for communication between said series of passages, the ports in each of said inner tubes being dis laced to one side of the radial plane intersecting the ports of the next adjacent tube or tubes, an annular header closing one end of said several annular passages with its central opening coinciding with the inlet to the innermost tube and a disk header closing the other end of said several annular passages except the outermost to provide a peripheral outlet from said series of passages.

7. A silencer comprising a plurality of tubes of difl'erent diameter concentrically arranged to provide a series of annular passages therebetween, said tubes being held in radially spaced relation by a series of circumferentially spaced indented integral portions of said several tubes adjacent the opposite ends thereof, the indented portions of adjacent tubes being in out of line relation, said several tubes being fastened to one another at said indented portions, an annular header closing one end of said several annular passages with its central opening coinciding with the inlet to the innermost tube and having an outwardly turned peripheral flange fastened to the end of said outermost tube, and a disk header closing the other end of said several annular passages except the outermost to provide a peripheral outlet from said series of 65 passages, and having an outwardly turned In tes nature.

timony whereof I have aflixed my sig- HIRAM PERCY MAXIM. 

